Determinants of infant mortality in Oromia region, Ethiopia

Introduction: Infant mortality is one of the commonest health-related indicators used to assess the health status of the community. Children born in Sub-Saharan Africa are at highest risk of infancy death in the world. Ethiopia, in Sub-Saharan Africa, is a country with high infant mortality. Oromia region is among the regions with high infant mortality rate in Ethiopia. Therefore, this study aimed to identify determinants of infant mortality in Oromia region, Ethiopia. Methods: The source of data for this study was 2019 Ethiopian Mini Demographic and Health Survey. Multivariable logistic regression model was employed to identify the determinants the infant mortality. An adjusted odds ratio (OR) with a 95% CI was used examine the determinants of infant mortality. Results: A total of 719 live births born 5 years preceding the survey were included. The infant mortality rate in the study area was 54 deaths per 1000 live births. The risk of dying in infancy was lower for females [adjusted OR (AOR): 0.518, 95% CI: 0.284, 0.945], health deliveries (AOR: 0.429, 95% CI: 0.235, 0.783), infants born to mothers attended ANC during pregnancy (AOR: 0.603, 95% CI: 0.489, 0.744), infants from families with wealth indices of medium (AOR: 0.715, 95% CI: 0.580, 0.882) and rich (AOR: 0.638, 95% CI: 0.425, 0.958) compared with the respective reference categories while it was higher for infants of multiple births (AOR: 2.241, 95% CI: 1.768, 2.841) compared with singletons. Conclusions: Infant mortality rate in the study area, Oromia region, is higher than the national figure. The study found that sex of child, birth type, antenatal care (ANC), place of delivery and wealth index of household were significant determinants of infant mortality. Therefore, concerned bodies should make awareness creation to mothers regarding ANC and encourage them to have ANC follow-up during pregnancy and deliver at health institution to improve the infant survival in the region.


Introduction
Infant mortality, the death of a child during the first year of life [1] , is one of the commonest health-related indicators used to assess the health status of the community [2,3] .
There has been global remarkable decline in infant mortality rate from 65 deaths per 1000 live births in 1990 to 28 deaths per 1000 live births in 2021 [4] . Despite this remarkable decline worldwide, Sub-Saharan Africa and Southern Asia remain the regions with the burden of child deaths falls hardest. Children born in sub-Saharan Africa continue to suffer the world's highest mortality rates [5] .
In 2021, Sub-Saharan Africa with 50 deaths per 1000 live births is a region with highest infant mortality rate compared to other Sustainable Development Goal regions [5] . The infant mortality rate in Ethiopia was 34 deaths per 1000 deaths in 2021 [4] .
The prevalence of infant mortality is higher in those regions where infants are particularly vulnerable to disease like malaria, diarrhoea, asphyxia, malnutrition and pneumonia [4] . The causes of infant mortality are highly associated with social wellbeing,

HIGHLIGHTS
• This study aimed to identify determinants infant mortality in Oroimia Region, Ethiopia. • Analysis was based on 2019 Ethiopian Mini Demographic and health Survey data. • Multivariable logistic model was employed to identify the determinants infant mortality. • The study found that sex of child, birth type, antenatal care (ANC) visit, place of delivery and wealth index of household were significant determinants of infant mortality. • Concerned bodies should make awareness creation to mothers regarding ANC and encourage them to have ANC follow-up during pregnancy and deliver at health institution to improve the infant survival in the region.
The most recent studies in Ethiopia and other African countries also show that nutritional status of child, birth asphyxia, distance to health facility, age of infant, maternal medical complications during pregnancy, prematurity, maternal death at birth, maternal education, maternal age, birth type and sex of child [40][41][42][43][44][45] were determinants of infant mortality.
According to the 2019 Ethiopian Mini Demographic and Health Survey (2019 EMDHS) report, infant mortality rate for the 5 years before the survey is 47 deaths per 1000 live births, which is equivalent to 1 in every 21 die before their first birthday. This result shows that infant mortality declined from 77 deaths per 1000 live births in 2005 to 47 deaths per 1000 live births in 2019, a 39% reduction over the past 14 years [40] . Even more efforts are needed to be made in Ethiopia to reduce infant mortality rate to the level targeted by sustainable development goal to be attained by 2030. The 2019 EMDHS report also shows that infant mortality rate in Oromia region is 62 deaths per 1000 live births, which is higher than the national figure, 47 deaths per 1000 live births [46] . Various studies on infant mortality have been conducted in Ethiopia; however, to the best of our knowledge, no study has been done at the regional level in the Oromia region using the national representative data. Therefore, this study aimed to identify the determinants of infant mortality in Oromia region, Ethiopia using 2019 EMDHS data.

Methods
Data source, study design and sample size Data used for this study were obtained from 2019 EMDHS data, which is a national representative cross-sectional survey data collected from 21 March to 28 June 2019. The 2019 EMDHS is the second EMDHS to be implemented in Ethiopia [46] . The study specifically used the data from 2019 EMDHS kids' data belonging to Oromia region. A sample of 719 children was included in the study.

Study variables
Response variable was death of live born before first birthday, which was coded as 1 if the live born died before first birthday and 0 otherwise, and independent variables were sex of child, birth type, birth order, ANC visits, place of residence, maternal age, maternal age at first birth, maternal education level, mother's marital status, religion, place of delivery, family size, parity, sex of household head and wealth status of household.

Statistical analysis
Data were analysed by SPSS version 26. The data were analysed using both descriptive and inferential statistics. Frequencies and percentages were used to summarise background characteristics of the participants. Both bivariate logistic regression analysis and Multivariable logistic regression analysis were done. Bivariate analysis was conducted to select candidate variables for multivariable logistic regression model. The multivariable logistic regression model was used to identify the determinants of infant mortality. The significance was considered at P value less than 0.05. Goodness of fit of the model was checked using Hosmer and Lemeshow test and the model with significance value of 0.595 found to be good fit.

Characteristics of study participants and bivariate analysis of infant mortality
Of the total of 719 live births included in this study, 39 (5.4%) were died before celebrating their first birth days indicating that infant mortality rate in the study area was 54 deaths per 1000 live births. About 51.2% of the children were males. Nearly ninetenth (87.9%) were born in rural areas. Majority (98.1%) of the children were singletons. About two-fifth (40.6%) of them had birth order of second to fourth. Nearly three-fifth (58.6%) were born at home. About four-fifth (79.8%) of them were born to mothers who had ANC visits. Regarding mother's age, nearly four-fifth (78.9%) of mothers aged less than 25 years. More than half (53.8%) of them aged less than 20 years at their first births. Majority (95.1%) of them were in union at a time of survey. Slightly more than half (52.3%) of them had not attended education at all and only 7.2% of them attended secondary and higher education. Nearly half (49.1%) of them were from households with wealth indices of poor (Table 1). Table 1 also shows that percentage of infant mortality was higher among males (6.8%). There was also higher percentage of infant mortality among multiple births (14.3%). The percentage of infant mortality was higher among infants born from mothers residing in rural areas (5.9%). Higher percentage of infant mortality (6.4%) was observed among infants born at home. Higher percentage of infant mortality was also observed among infants born to mothers who did not attend ANC (7.6%).

Factors associated with infant mortality in Oromia region, Ethiopia
The result multivariable logistic regression analysis shows that sex of infant, birth type, ANC visit, place of delivery and wealth status of household significantly determinant infant mortality at 5% level of significance. The odds of infant mortality among females was 0.518 [adjusted odds ratio (AOR): 0.518, 95% CI: 0.284, 0.945] times lower than males. The odds of infant mortality among infants of multiple births was 2.241 (AOR: 2.241, 95% CI: 1.768, 2.841) times higher than infants of single births. Infants born in health institutions were (AOR: 0.429, 95% CI: 0.235, 0.783) less likely to die than infants born at home. Infants born to mothers who visited ANC were (AOR: 0.603, 95% CI: 0.489, 0.744) times less likely to die than infants born mothers who did not attend ANC. Infants from families with wealth indices of medium and rich were (AOR: 0.715, 95% CI: 0.580, 0.882) and (AOR: 0.638, 95% CI: 0.425, 0.958) times, respectively, less likely to die than infants from poor families ( Table 2).

Discussion
This study was aimed to identify determinants of infant mortality in Oromia region, Ethiopia. A total of 719 live born, of which 39 (5.4%) were died before celebrating first birthday, were included in the study. The multivariable logistic regression analysis revealed that sex of infant significantly determines infant mortality. Female babies were at lower risk of infancy mortality than males. This could be due to that girls are biologically stronger and less susceptible to diseases and death. This agrees with the results of studies [7,13,21,24,32,45,47] .
In this study, place of delivery was also found to be significant determinant of infant mortality. Infants born in health institutions were less likely to die than infants born at home. This is consistent with studies [7,12,24,36,38,39] . This might be due to the immediate access to care among babies born at health institutions by skilled birth attendants.
This study also found that infants born to mothers who had ANC visit were less likely to die than infants born to mothers who had no ANC visit. This might be because of that mother who had ANC visit may be aware of any danger signs of pregnancy and underlying medical conditions and may take treatment for the problems that can improve the quality of infant life. This result agrees with studies [21,48] . In addition, the study found that infant mortality decreases with increased wealth status of household. This result is consistent with studies [13,31,49,50] . In the study, it was also found that multiple births infants were at higher risk of death than single infants before celebrating first birthday. This result is consistent with results of the studies [7,10,21,24,32,36,45] . The possible reason could be that twins are more likely to be born prematurely, and lower birth weight than single birth infants [51] .

Strength and limitation of the study
The main strength of this study was that it was based on the national representative survey data. One of the limitations of the study was that it did not include variables such as size of child at birth, mothers working status, educational status of father, preceding birth interval, and breastfeeding status, that might determine infant mortality due to high missing values and unavailability in the dataset. The other limitation was that the sample size of 39 deaths was very small that might affect conclusion.

Conclusion
The overall infant mortality rate in this study was 54 deaths per 1000 live births. Infant mortality rate among male babies was 68 deaths per 1000 live births. It was 59 deaths per 1000 live births among babies born in rural areas. Infant mortality rate among multiple births was 143 deaths per 1000 live births. Infant mortality rate among home delivered babies was 64 deaths per 1000 live births and it was 76 deaths per 1000 live births among babies born from mothers who did not attend ANC during their pregnancies. It was found that sex of child, birth type, ANC visit, place of delivery and wealth index of household were significant determinants of infant mortality in Oromia region, Ethiopia. Male babies were at higher risk of dying before first birthday compared to female babies. Babies of multiple births were at higher risk of dying before first birthday compared to singletons.
Babies born at health institutions were at lower risk of dying before first birthday compared with those born at home. The risk of infancy death was lower among babies born to mothers who had ANC visits than those born to mothers who did not have ANC visits during their pregnancies. Babies born from poor families were at higher risk of dying before first birthday compared with those born from families with wealth indices of medium and rich. Therefore, concerned bodies should make awareness creation to mothers regarding ANC, and encourage them to have ANC follow-up during pregnancy and deliver at health institution to improve the infant survival in the region. In addition, further studies need to be conducted considering those factors which were not included in this study because of unavailability/high missing values in the dataset we used.

Ethical approval and consent to participate
The data are secondary data and publicly available and has no personal identifiers.

Consent
Not applicable.

Sources of funding
This study was not funded.

Conflicts of interest disclosure
Authors declare that they do not have conflict of interest.

Research registration unique identifying number (UIN)
NA.

Data availability
All data used for the analysis in this study are available upon reasonable request from corresponding author.

Provenance and peer review
Not commissioned, externally peer-reviewed